Safety-crank



0. GREEN.

Patented J 11118 28, 1921.4

2 SHEETS-SHEET l.

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C. GREEN.

SAFETY CRANK. -MILICATJON FILED AUG.25, (920 1 383,10 1 Patented June 28, 1921. I 2 snags-SHEET 2.,

UNITED STATES PATENT OFFICE.

' SAFETY-CRANK.

Specification of Letters Patent.

Patented June 28, 1921.

Application filed August 25, 1920. Serial No. 40 3,1102.

T 0 all 10/2 cm it may concern:

Be it known that I, CHEs'rEn GREEN, a citizen of the United States, and resident of Cornwall Landing, in the county of Orange and State of New York, have invented a new and Improved Safety-Crank, of which the following is a full, clear, and exact description.

It is well appreciated that numerous accidents have occurred in connection -with cranking internal combustion engines, due to a premature ignition in one of the cylinders which has resulted in what is com monly known as a back fire and consequential back-lash, on the part of the start ing crank. Y

WVith this. in view, numerous cranks have been provided which have sought to overcome this defect. Most of these cranks have in mind the provision of a certain construction which wouldauto'matically serve to withdraw the pawl, or engagingend of the crank, out of engagement with the end of the crank shaft upon a back fire occurring. Almost without exception, however, these devices have proven impractical for the reason-that a certain amount of back-lash on the part of the crank handle necessarily existed before the parts moved out of engagement. This back lash usually through an arc of approximately 90 was sufficient to causea serious injury to the operator, especially if he were exerting any unusual amount of force in an effort to turn'the motor over.

Further, it has often occurred, that safety cranks of this type have entirely failed to operate so that no benefits have been derived from: their use, in an emergency when a backlash occurred.

Having these defects in mind,I have now constructed a safety crank which is particularly adapted for use in turning an internal combustion engine over for starting the same, but which is not necessarily limited to this adaptation, and by means of which, upon .a back fire occurring,.a retrograde movement. will result through an arc of such smallness as to be well nigh imperceptible, so that no danger of injuryto the operator may result.

A further object of my invention is the construction of a safety crank which-shall operate under all conditions in the event of a back fire so thatthe same may be implicitly relied upon to function.

Reference is had to the attached sheet of drawings as illustrating practical embodiments of my invention, and in which draw- 1ngs: r a

Figure 1 is a front view of a safety crank constructed in accordance with my invention. a r

Fig. 2 is an enlarged sectional side view taken along the line 2-2 of Fig. 1', and

Figs. 3 and 4 are fragmentary sectional views taken along the lines 3- 8 and JP-4- respectively of Fig. 2 in the direction of the arrows. v v

In these views the reference numeral 5 indicates a pair of spaced annular plates, betweenwhich is interposed a ring 6 presenting a ratchet '7 in its inner face, such ring being retained in applied position by any suitable means such as screws 8.

A pair of ears 9, are rigidly secured to these portions, and serve to retain the whole in applied position upon'the front of a motor vehicle or other position to which they may be attached,'by virtue- 0f bolts or other suitable retaining means 10, which engage a fixedportion of the vehicle or other element. r

A crank handle 11 is" pivotally suspended as at 12 from a bracket'13, which bracket forms an integral portion of a hollowed disk 14. The disk 14 presentsa projecting portion in the nature of a sleeve 15, such disk further providing an inwardly extending annular ange 16 adjacent the base of said sleeve'15 for a purpose hereinafter more fully 3 specified.

A male disk 17 is adapted to extend into the hollowed. disk, such' former disk presenting a tubular extension 18 terminating at a point beyond either edge of'the sleeve 15. An expansion spring 19 is conveniently interposed between the flange 16 and a washer 20 retained in applied position by means of a nut 21, which is secured to the tubular extension 18. y

It will be understood that the hollowed disk ltand the male disk 17 willbe moved toward one another, and will serve to frictionally engage and cause interengagement between a plurality of clutch gears 22. The disks 22 may be of any suitable number, and it is to be noted that alternate disks are keyed to the male disks17 as at 23, and to the hollowed disk 14 as at 24L respectively.

By v1 tue of this construction it will be readily understood that the rotational force exerted by the crank 11 will be imparted to the hollowed disk 1 1 whichin turn will exert rotational force upon the clutch disks 22,

' this latter action transmitting its force to the male disk 17; b

A crank shaft engaging member 25, of any desirable construction is positioned adj acent' the outer end of the disk 17,1and is retained in this position by virtue of a squared'shait 26 longitudinally movable within the disk 17,; which shaft is continuedas at 27, and terminates at a point: beyond the outer end of the tubular extension 18 in a plane at which the inner end of the crank 11 may engage the same.

A spring 28 is interposed between a portion of the extension 18 and an adjustable stop 29 secured adjacent the outer end of the shaft 27 so that the engaging member will be normally retained in its retracted position (indicated in fulllines) v 't being noted however that upon the crank 11 being swung to the position indicated in dotted lines inFig. 2, that the shaft 26 will be projected, causing a projection on r the part of the engaging member 25 to the position also indicated in dotted lines, at which position it may engage the end of the-crank shaft or other object to 3 be turned;

Finally it will'be noted that the outer face of the hollowed; disk 14 is conveniently formed-with anoutwardly extending portion 30 approximately intermediate its side edges, which portion r 14', and

Figs. 3 and 41. Further, it will be seen that the individual pawls 31 areso arranged that certain of the same are at all tim'esadjacent or substantially adjacent one of the teeth of thelratchet 7 for a purpose hereinafter brought out.

It will now be noted in operation, assuming that'the ears 9'have been attached in the manner'aforestated, to properly position the parts that the crank handle 11 may primarily be rocked'around its pivot 12, which will result in a projection on the part of the shaft- 2 627, and consequently a projection of the engaging member 25 secured thereto. This member will nowhave been moved to the position'indicated in dotted lines, at which point it will engage theshaft to be rotated. i V

It ,will be obvious, due to the frictional engagement existing between the disks 14 and 17 and thefinterposed plurality of disks 22, and the connection of this latter,

that upon a rotational force being imparted to the crank 11 that this force will be in turn transmitted to the engaging member 25 ina manner which has been afOredescribed.

Now assuming that a back fire occurs, or

.in other words, that an anti-clockwise mo tion is imparted to the engaging member 25, it will be seen that this rotational force will be imparted to the male disk17, and by 'virtue of the fact that the centermostplate 22 is keyed to this disk as at 23, this force will be imparted to the platespecified, and, in i turn, by virtue of the vfrictional inter-en gagement of the plates-forwrdisks 22, and the connection of certain of the same, as at 2 1 to the hollowed disk 1 1, this latter member will be turned, V 1 1 However, upon this motion being imparted, it will be seen that by virtue of the fact that the pawls 31 are not spacedf in such a manneras to 'aline or be equidis:

tant from the teeth of the ratchet 7, that the most imperceptible retrograde motion will permit one of thesepawls to engage its corresponding ratchet which will materially result in cessation of turning on the-part of the hollowed disk 14, by virtue of theiact that this member as aforedescribed, is se- 7 cured by the ears 9 to a fixed'portion of the element with which it is associated.

The disk l i now being incapable of turning farther will prevent any motion on the part of theplates 22 which are associated as at21. The male disks l7 howeverwill continue to move. in thedirection imparted to it by the back fire, and it will be seen that this will result in the clutch, formed by the interposed plates and faces of the'hollowed disk and male disk, slipping. Obviously immediately upon a back fire occurring the handle 11 may be swung downwardly, thus relieving the strain upon the parts by moving the engaging member. back to its normal position. a i v Obviously numerous modifications of structure might readily be resorted to without in, the least departing fromfthel spirit of my invention, which I claim as:'-

1.;A safety crank including a clutch comprising a hollowed plate,,a maleplate, a lurality of plates interposed between said rst named plates, certain of said latter plates being secured to said hollowed plate, the further plates of saidclutch being-secured to said male plate, asleeve forming a part of said hollowed plate, an outwardly extending flange adjacent the base of'said-sleeve,

an extending portion forming apart oi said male plate and projecting through said sleeve and beyond the same, a spring interposed between said' flange and projecting ber secured to said male plates, andmeans for rotating said hollowed plates.

2. A safety crank including a clutch comprising a hollowed plate, a male plate, a plurality of plates interposed between said first named plates, certain of said latter plates being secured to said hollowed plate, the further plates of said clutch being secured to said male plate, a sleeve forming a part of said hollowed plate, a forwardly extending flange adjacent the base of said sleeve, an extending' ortion forming a part of said male plate and projecting through said sleeve and beyond the same, a spring interposed between said flange and project ing portion of the male plate, a shaft extending through said male plate and beyond the ends of the same, an engaging member secured to one of the ends of said shaft, a crank handle secured to said hollowed plate, the end of said pivotally mounted crank being adapted to engage the end of said shaft for projecting the same.

8. A safety crank including a clutch comprising a hollowed plate, a male plate, a

plurality of plates interposed between said first named plates, certain of said latter plates being secured to said hollowed plate, the further plates of said clutch being secured to said male plate, a sleeve forming a part of said hollowed plate, a forwardly extending flange adjacent the base of said sleeve, an extending portion forming a part of said male plate and projecting through said sleeve and beyond the same, a spring interposed between said flange and projecting portion of the male plate, a shaft extending through said male plate and beyond the ends of the same, an engaging member secured to one of the ends of said shaft, a crank handle secured to said hollowed plate, the end of said pivotally mounted crank being adapted to engage the end of said shaft for projecting the same, and a spring interposed between the end of said shaft and said male plate for normally retaining said shaft and engaging member in retracted position. I

CHESTER GREEN. 

